`crate.annotate` has no way to remove optional features like `crate.override` did

In the previous `crates_universe` functionality, `crate.override` could be used to remove optional features. There doesn't seem to be any similar functionality in the corresponding `crate.annotate` feature now that rules_rust has switched to `crates_repository`. This might be useful for turning off some default features, for example. See #1168 for more context.